CVE-2022-29546Public exploitNetwork attack vector

Service interruption via unterminated processing instruction

Published Apr 25, 2022 · Updated Aug 3, 2024

Denial of service in HtmlUnit NekoHtml Parser before 2.61.0 allows remote attackers to exhaust heap memory via crafted PI data. HTMLScanner.scanPI() fails to treat end-of-file after a slash or question mark as termination, so it repeatedly appends data to fStringBuffer. Any application that parses attacker-controlled HTML can hang or crash when the Java heap is exhausted; no authentication or user interaction is required.

CVSS severity7.5
High
EPSS probability1.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in HtmlUnit NekoHtml Parser before 2.61.0 allows remote attackers to exhaust heap memory via crafted PI data. HTMLScanner.scanPI() fails to treat end-of-file after a slash or question mark as termination, so it repeatedly appends data to fStringBuffer. Any application that parses attacker-controlled HTML can hang or crash when the Java heap is exhausted; no authentication or user interaction is required.

The record

CVE
CVE-2022-29546
Published
Apr 25, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 25, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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